Closed containers, particularly rigid or semi-rigid glass laboratory bottles or flasks with straight or tapered internal neck plugs, caps or stoppers, generally have a seal, sometimes caused by atmospheric pressure or may otherwise be frozen or jammed. This makes the containers difficult to open, and forcing the lid and container apart tends to damage the glass or other material forming the components.
Various techniques and apparatus have been used in the past to unseal or force open jammed containers with limited success. Apparatus which require rotation of the lid or cover on the container to break the seal have a tendency to damage the neck of the container, particularly when the seal is especially tight. Furthermore, some container-opening apparatus are designed only for specific types of containers and lids, particularly glass jars with rubber gaskets, often used in home food preservation.
For example, U.S. Pat. Nos. 1,450,168; 1,350,180; 1,279,441; and 1,357,914 disclose implements for removing lids from glass jars. Each of the implements comprises a loop of flexible wire attached to a handle. The loop is placed between the jar and lid, and the handle to which the loop is secured is used as a lever against the neck of the container to force or wedge the wire loop into the seal to thereby break it. In U.S. Pat. No. 1,389,818 a jar opener comprises a wire loop, secured to two handles with one of each handle pivotally attached to a metal disk. The ends of the wire loop are connected to the handles on opposite sides of a pivot pin. The handles are pivoted to be diametrically opposed to each other, thereby forcing the wire loop into the seal between the container lid and the container.
U.S. Pat. No. 2,458,393 discloses an implement for turning threaded container lids, comprising a handle attached to a loop of frictional cord to encircle the container lid. The cord is imparted with a pushing, circular motion in the direction in which it is desired to turn the lid.
In U.S. Pat. No. 2,013,209 a cable serving as a grip for a cap, is clamped to a handle by a suitable lever. A continuous tilting movement of the handle loosens the cap from the mouth of the jar.
Thus, in the prior art, leveraged pressure has been applied against the neck of a container or a container lid to force open any seal between the two. A danger inherent in this kind of mechanism is in damage to the container, lid or both.